Filter for a Smoking Article

ABSTRACT

A filter element ( 214 ) for a smoking article comprising a plug of filter material ( 210 ) having a longitudinally extending surface ( 213 ), a wrapper ( 220 ) wrapped around the longitudinally extending surface of the plug of filter material and a tobacco product ( 240 ) located between the longitudinally extending surface of the plug of filter material and the wrapper so as to cover at least a part of the longitudinally extending surface.

FIELD OF THE INVENTION

This invention relates to a filter for a smoking article.

BACKGROUND TO THE INVENTION

As used herein, the term “smoking article” includes smokeable products such as cigarettes, cigars and cigarillos whether based on tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes and also heat-not-burn products.

It is well known that filtration of smoke in a smoking article such as a cigarette may adversely affect the taste and flavour characteristics of a product when smoked. Filters commonly include adsorbent materials such as activated carbon to reduce certain components of the smoke during smoking. Unfortunately activated carbon in a filter can significantly affect the taste/flavour characteristics of a cigarette.

SUMMARY OF THE INVENTION

According to an aspect of the invention, there is provided a filter element for a smoking article comprising a plug of filter material having a longitudinally extending surface, a wrapper wrapped around the longitudinally extending surface of the plug of filter material and a tobacco product provided between the longitudinally extending surface of the plug of filter material and the wrapper so as to cover at least a part of the longitudinally extending surface.

The tobacco product may cover only a part of the longitudinally extending surface of the plug of filter material.

The tobacco product may be provided in longitudinal stripes between the longitudinally extending surface of the plug of filter material and the wrapper.

The tobacco product may cover substantially an entire inner surface of the wrapper.

The tobacco product may be in contact with the longitudinally extending surface of the plug of filter material.

The tobacco product may be adhered to an inner surface of the wrapper.

An adhesive comprising the tobacco product may be applied to an inner surface of the wrapper.

The tobacco product may comprise shredded tobacco.

The tobacco product may comprise powdered tobacco.

The tobacco product may comprise shredded or powdered reconstituted tobacco.

The tobacco product may comprise cut tobacco.

According to another aspect of the invention, there is provided a filter for a smoking article comprising one or more of the filter elements.

A section of the filter may comprise activated carbon and the coverage of the tobacco product may be confined to the longitudinally extending surface of this section.

According to another aspect of the invention, there is provided a filter element for a smoking article, comprising a plug of filter material having a longitudinally extending surface, and a wrapper wrapped around the longitudinally extending surface of the plug of filter material, wherein the wrapper comprises reconstituted tobacco material.

The reconstituted tobacco material may be reconstituted tobacco paper.

The wrapper may comprise a plug wrap.

According to another aspect of the invention, there is provided a smoking article including the filter element described above.

According to another aspect of the invention, there is provided a filter element for a smoking article, comprising a plug of filter material having a longitudinally extending surface, and a wrapper wrapped around the longitudinally extending surface of the plug of filter material, wherein the wrapper comprises reconstituted tobacco material.

The reconstituted tobacco material may be reconstituted tobacco paper.

The wrapper may comprise a plug wrap.

15. A smoking article comprising a filter element according to claim 12, 13 or 14.

According to another aspect of the invention, there is provided a method of manufacturing a filter element for a smoking article comprising providing a tobacco product between a longitudinally extending surface of a plug of filter material and a wrapper so as to cover at least a part of the longitudinally extending surface.

The method may comprise adhering the tobacco product to an inner surface of the wrapper.

The method may comprise confining coverage of the tobacco product to only a part of the longitudinally extending surface.

The method may further comprise confining the tobacco product to the longitudinally extending surface of a section of the filter element comprising activated carbon.

The method may comprise applying an adhesive comprising the tobacco product to an inner surface of the wrapper.

BRIEF DESCRIPTION OF THE FIGURES

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of a smoking article including a rod of smokeable material, a filter and tipping paper attaching the rod and filter together.

FIG. 2 is a perspective view of a plug of filter material having a first end face, a second end face and a longitudinally extending surface.

FIG. 3 is perspective view of a filter element including a plug of filter material and a wrapper in the form of a plug wrap.

FIG. 4 is a perspective view of a filter element in which a tobacco product is adhered to an inner surface of the plug wrap.

FIG. 5 is a perspective view of first and second filter elements with abutting end faces.

FIG. 6 is a cross-sectional view of first and second filter elements with abutting end faces, in which the first filter element includes activated carbon.

FIG. 7 is a cross-sectional view of an end face of a filter element including activated carbon.

FIG. 8 is a perspective view of a filter comprising abutting first and second filter elements wrapped with an outer wrapper.

FIG. 9 is a perspective view of first and second filter elements for a filter, in which the second filter element includes a tobacco product adhered to the inner surface of its plug wrap.

FIG. 10 is a perspective view of a filter element in which stripes of adhesive are applied to the inner surface of the plug wrap.

FIG. 11 illustrates a process for preparing a plug wrap for use in a filter element.

FIG. 12 is a perspective illustration of the wrapping of a cylindrical tow of filter material by a wrapper.

FIG. 13 shows a sequence of method steps for manufacturing a filter element.

EXEMPLARY EMBODIMENTS OF THE INVENTION

A smoking article in the form of a cigarette 100 includes a filter 200 in accordance with the invention. Referring to FIG. 1, the cigarette 100 comprises a generally cylindrical paper-wrapped rod 110 of smokeable material such as tobacco, which is co-axially attached to the filter 200 by tipping paper 300 glued around one end of the rod 110 and the filter 200. The filter 200 comprises a generally cylindrical tow of filter material.

The cylindrical tow of filter material comprises one or more sections, each of which may have a different material composition. In this example of the invention, as described below, each section corresponds to one of a plurality of generally cylindrical plugs of filter material 210 in one of a corresponding number of discrete filter elements which make up the filter 200. However, alternatively, the filter 200 may be of integral construction such that the individual sections correspond to portions of a single, continuous plug of filter material in a single filter element.

A general example of a filter element 214 for forming a filter 200 in accordance with the invention is described below with reference to FIGS. 2 to 4. Referring to FIG. 2, the plug of filter material 210 in the filter element 214 has first and second generally circular end faces 211, 212 and a circumferential or longitudinally extending surface 213 substantially perpendicular to the first and second end faces 211, 212.

The plug of filter material 210 in the filter element 214 is wrapped by a layer of sheet material in the form of a wrapper, or plug wrap 220. As shown by FIG. 3, the plug wrap 220 is wrapped around the longitudinally extending surface 213 of the plug of filter material 210 so as to leave the first and second end faces 211, 212 of the plug 210 open. Typically, the plug wrap 220 is held in place around the plug of filter material 210 by gluing along a seam of overlapping material. This may be achieved using a stripe of suitable adhesive 230, such as a conventional PVA material. Alternatively, the plug wrap 220 could be adhered directly to the surface 213 of the filter material 210, for example by applying a plurality of stripes of adhesive 230 to the inner surface 221 of the plug wrap 220. The application of stripes of adhesive 230 to the plug wrap 230 is shown in FIG. 11.

The plug wrap 220 may be formed of conventional paper materials. However, the plug wrap 220 may alternatively or additionally comprise tobacco or reconstituted tobacco material. The plug wrap 220 could also be formed entirely from reconstituted tobacco material, such as a sheet of reconstituted tobacco paper. The reconstituted tobacco material may have a different colour to the plug of filter material in order to provide visual differentiation. For example, the reconstituted tobacco material may have a bright colour such as yellow or blue to clearly contrast with a white cellulose acetate plug of filter material and a brown tipping paper.

Referring to FIG. 4, the filter element 214 further includes a tobacco product 240 located between the longitudinally extending surface 213 of its plug of filter material 210 and the inner surface 221 of its plug wrap 220. The tobacco product 240 may, for example, take the form of shredded or powdered tobacco. Typically, the tobacco product 240 will take the form of cut tobacco. Alternatively, the tobacco product 240 may comprise strands or particles of reconstituted tobacco or tobacco containing paper, or may be any combination of the above.

The tobacco product 240 may be adhered to the inner surface 221 of the plug wrap 220 using a suitable adhesive, such that the tobacco product 240 covers all or a part of the longitudinally extending surface 213 of the plug of filter material 210 when wrapped by the plug wrap 220. When the plug wrap 220 is wrapped around the plug of filter material 210, the tobacco product 240 may be in direct contact with the longitudinally extending surface 213 of the plug of filter material 210.

Suitably, as shown in FIG. 5 and as briefly outlined above, the filter 200 comprises a plurality of filter elements. An example of a filter 200 in accordance with the invention is discussed below in relation to FIGS. 6 to 8. In this example of the invention, the filter 200 comprises a first filter element 214 containing a tobacco product 240 as described above, and a second filter element 215 not containing a tobacco product. The form and manufacture of the second filter element 215 may simply correspond to that of the first filter element 214, with the tobacco product 240 omitted. However, as described below, in this example of the invention the first filter element additionally comprises activated an adsorbent such as activated carbon.

The first and second filter elements 214, 215 are generally cylindrical, discrete filter elements 214, 215 of substantially equivalent diameter. In this example, the filter material 210 in the second filter element 215 is composed of cellulose acetate, whilst the filter material 210 in the first filter element 214 comprises both cellulose acetate and an adsorbent such as activated carbon. The activated carbon may be in the form of granular activated carbon 216 and is distributed evenly throughout the volume of the plug of cellulose acetate 210 in a “Dalmatian” style, as is known in the art. Cross-sectional views showing this arrangement are provided in FIGS. 6 and 7. Alternatively, the activated carbon may be sprinkled onto a sticky exterior surface 213 of the plug of cellulose acetate 210, or may be adhered to a cotton thread surrounded by the plug of cellulose acetate 210. The activated carbon could also be held in a cavity surrounded by the plug of cellulose acetate 210.

Although the first and second filter elements 214, 215 are shown in FIGS. 5 and 6 as being substantially equal in length, it will be appreciated that the elements 214, 215 could alternatively be of different lengths. In addition, it will be appreciated that the filter 200 may comprise more than two filter elements. For example, the filter 200 may comprise first and second filter elements composed of cellulose acetate and a third filter element comprising cellulose acetate and activated carbon, as described above. In one example, the filter element comprising activated carbon is sandwiched between the two elements composed of cellulose acetate. However, it will be appreciated that the filter elements 214, 215 may be arrayed in the filter 200 in a plurality of alternative orders. At least one of the filter elements contains a tobacco product 240 as described above.

As shown by FIGS. 5 and 6, the filter elements 214, 215 are arranged longitudinally of one another with the end face 211, 212 of each filter element 214, 215 abutting the next. Referring to FIG. 8, the filter elements 214, 215 are wrapped by an outer wrapper 250, which may be held in place around the filter elements 214, 215 by gluing along a seam of overlapping material in a similar manner to the plug wraps 220. The outer wrapper 250 may complete the assembly of the filter 200.

Referring back to FIG. 1, the filter 200 is located at a mouth-end of the smoking article 100 such that a gaseous flow, comprising smoke drawn from the rod 110 of smokeable material, moves through the filter 200 before entering the mouth of a smoker. The tobacco product 240 is located in one or more filter elements 214, 215 between the inner surface 221 of a plug wrap 220 and the longitudinally extending surface 213 of a plug of filter material 210, as described in relation to FIG. 4. In this way, the tobacco product 240 is in close proximity with the path of the gaseous flow as it moves through the filter 200 and is therefore able to affect the characteristics of the gaseous flow before the flow reaches the smoker's mouth.

The tobacco product 240 may, for example, affect the overall properties of the gaseous flow such that the taste and flavour of the gaseous flow are improved, making the gaseous flow more appealing to the smoker. One application of the tobacco product 240 is to replace a degree of the taste and flavour characteristics of the gaseous flow which may be lost as the gaseous flow moves through the filter material 210. In this regard, the coverage of the tobacco product 240 may be confined to the longitudinally extending surface 213 of a section of the filter material 210, either in the filter 200 or a single filter element 214, 215, which comprises activated carbon, as activated carbon is known to affect the taste and flavour of tobacco smoke. For example, as is shown in FIG. 9, in this example of the invention the tobacco product 240 is only present in the filter element 214 which comprises activated carbon 216.

More generally, the tobacco product 240 may be adhered to the plug wrap 220 so as to provide a substantially even coverage over the surface 213 of the filter material 210 in the filter 200. Alternatively, different areas of the surface 213 of the filter material 210, either over the whole filter 200 or a single filter element 214, 215, may be covered by different loadings of the tobacco product 240. For example, the tobacco product 240 may be provided in a plurality of stripes, as explained in more detail below.

Referring to FIGS. 10 and 11, stripes of adhesive 230 may be applied to the inner surface 221 of a sheet of plug wrap 220. The stripes of adhesive 230 may provide a means for adhering the tobacco product 240 to the inner surface 221 of the plug wrap 220, such that the tobacco product 240 forms longitudinal stripes on the surface 221 of the plug wrap 220. The stripes of adhesive 230 could feasibly be oriented in any direction. In addition, or as an alternative, to adhering the tobacco product 240 to the plug wrap 220, the adhesive 230 could provide a means for adhering the plug wrap 220 to the filter material 210.

A possible method of applying the tobacco product 240 to the plug wrap 220 is to mix the tobacco product 240 with the adhesive 230 prior to it being applied to the plug wrap 220. Referring to FIG. 11, this may comprise passing a planar sheet of plug wrap 220 through a gluing station 400 in the direction of arrow A, at which application nozzles 500 apply the stripes of adhesive 230 in parallel, longitudinally along the inner surface 221 of the plug wrap 220. The adhesive 230 for the stripes may be applied through the nozzles 500 from a tank 600. If the tobacco product 240 is mixed with the adhesive 230 as described above, the nozzles 500 may also be responsible for applying the tobacco product 240 to the inner surface 221 of the plug wrap 220. If the tobacco product 240 is not mixed with the adhesive 230, the tobacco product 240 may be applied to the inner surface 221 of the plug wrap 220 by another application means. For example, the tobacco product 240 may be sprinkled or sprayed over the plug wrap 220 such that it adheres to the plug wrap's inner surface 221.

Alternatively, the adhesive 230 may be applied to the inner surface 221 of the plug wrap 220 by any other suitable application method. For example, adhesive 230 may be sprayed over the inner surface of the plug wrap 220.

Referring to FIG. 12, to create a filter element 214, a planar sheet of plug wrap 220 and a generally cylindrical tow of suitable filter material may be fed to a wrapping station 700 in the direction of arrow B. Here, the plug wrap 220 is wrapped around the tow of filter material and glued by a gluing nozzle 800 so that the plug wrap 220 completely encompasses the longitudinal surface 213 of the filter material. The filter material and surrounding plug wrap may then be cut into lengths to create a plurality of filter elements 214, 215 suitable for use in individual cigarettes 100. This is illustrated schematically by dotted outline 1000 of FIG. 12. The steps of a method for forming a filter element in accordance with the invention are shown by S1 to S6 in FIG. 13.

The invention also includes further modifications and variations falling within the scope of the claims. 

1. A filter element for a smoking article comprising: a plug of filter material having a longitudinally extending surface; a plug wrap wrapped around the longitudinally extending surface of the plug of filter material; and a tobacco product provided between the longitudinally extending surface of the plug of filter material and the plug wrap and configured to cover at least a part of the longitudinally extending surface, wherein a section of the filter material comprises activated carbon and the coverage of the tobacco product is confined to a longitudinally extending surface of the section comprising activated carbon.
 2. The filter element according to claim 1, wherein the tobacco product covers only a part of the longitudinally extending surface of the plug of filter material.
 3. The filter element according to claim 1, wherein the tobacco product is provided in longitudinal stripes between said surface of the plug of filter material and the plug wrap.
 4. The filter element according to claim 1, wherein the tobacco product is in contact with the longitudinally extending surface of the plug of filter material.
 5. The filter element according to claim 1, wherein the tobacco product is adhered to an inner surface of the plug wrap.
 6. The filter element according to claim 1, wherein an adhesive comprising the tobacco product is applied to an inner surface of the plug wrap.
 7. The filter element according to claim 1, wherein the tobacco product comprises shredded tobacco.
 8. A filter for a smoking article comprising one or more filter elements according to claim
 1. 9. A filter comprising at least two filter elements according to claim 1, wherein a first of the filter elements comprises activated carbon and a second of the filter elements does not comprise activated carbon, the tobacco product covering a longitudinally extending surface of the first filter element.
 10. A smoking article including the filter element according to claim
 1. 11. A filter element for a smoking article, comprising: a plug of filter material having a longitudinally extending surface; and a plug wrap comprising reconstituted tobacco material wrapped around the longitudinally extending surface of the plug of filter material; wherein a section of the filter material comprises activated carbon and the reconstituted tobacco material is confined to a longitudinally extending surface of the section comprising activated carbon.
 12. The filter element according to claim ii, wherein the reconstituted tobacco material is reconstituted tobacco paper.
 13. A smoking article comprising the filter element according to claim
 11. 14. A method of manufacturing a filter element for a smoking article, comprising providing a tobacco product between a longitudinally extending surface of a plug of filter material and a plug wrap, the tobacco product covering at least a part of the longitudinally extending surface, wherein a section of the filter material comprises activated carbon and the tobacco product is confined to a longitudinally extending surface of the section comprising activated carbon.
 15. The method according to claim 14, comprising adhering the tobacco product to an inner surface of the plug wrap.
 16. The method according to claim 14, comprising applying an adhesive comprising the tobacco product to an inner surface of the plug wrap.
 17. A method of manufacturing a filter element for a smoking article, comprising providing a plug wrap comprising reconstituted tobacco material around a longitudinally extending surface of a plug of filter material, wherein a section of the filter material comprises activated carbon and the reconstituted tobacco material is confined to a longitudinally extending surface of the section comprising activated carbon.
 18. The method according to claim 17, wherein the reconstituted tobacco material is reconstituted tobacco paper. 